Because there are hundreds of symbols that may be used in a plumbing blueprint, it is necessary for someone who is unfamiliar with plumbing systems to first obtain a guide to plumbing blueprint symbols. Lists of symbols are available online, and print guides to plumbing symbols are available for sale or to borrow at many libraries.
In the house-building process, it is the architects who are initially responsible for drawing up the blueprints, including the plumbing blueprints. For this reason, architects work closely with plumbers to remain up to speed on changes in plumbing codes and symbols. Most blueprints are accompanied with a schedule that lists the symbols used in the print but may not include the definitions of these symbols.
A guide to blueprint symbols makes it easier to identify the symbols in the accompanying schedule. The schedule also helps identify major plumbing fixtures, such as sinks, showers, bathtubs and toilets. Knowing the locations of the major fixtures makes it easier to trace the drain lines and vents throughout the house. It is also important to know the location of gas, sewer connections and water lines used for radiant heating so as not to cause damage to pre-existing systems.